What are brick slips?
Brick slips are thin brick faces, usually of fired clay, that are bonded to a flat substrate and then pointed so the wall looks like facing brickwork. In Dutch they are called steenstrips. They are either sawn from whole bricks or made as thin units from the start. Corner slips (L-shaped “pistols”) make an external corner look as if it were built from full bricks.
Thickness and types
Thickness depends on the system. Many panel and insulation systems use slips of about 20 mm; some render-applied slips are only a few millimetres thick. Besides clay there are concrete, natural stone and polymer-bound mineral slips, which differ in weight, frost resistance and fire behaviour.
Where they are used
The most common use is as the finish of an external wall insulation system: insulation boards fixed to the existing wall, a base coat, adhesive, slips and pointing mortar. You get a brick look without building a new outer leaf and without needing a wider foundation. Slips are also bonded to precast panels in the factory and used indoors as a feature finish.
Application
- Use one tested system. Outdoors, insulation, adhesive, mesh, slips and pointing mortar should come from a single certified system. Do not mix products from different suppliers.
- Prepare the substrate. It must be flat, clean, sound and dry. Remove loose paint and friable render first.
- Choose frost-resistant slips for external walls and ask for the declaration of performance.
- Plan movement joints and details at windows, eaves and the base as the system requires.
- Check fire rules early. Requirements depend on country and building height. In England, external walls of “relevant buildings” (with a storey of 18 m or more) must use materials classed A2-s1,d0 or A1, and that applies to the whole slip system, not just the brick.
Common mistake: fixing slips with dabs of adhesive on the back. Water collects in the voids and frost pushes the slips off. Bond them with full adhesive coverage as the system specifies.
Related terms
- Sawn brick
- Split stone
- External wall insulation
- Adhesive mortar
- Facing brickwork
- Cladding
- Fire classification
Want to know more about building terms? Visit our knowledge base at fredsdiyplans.com.